1. Field of the Invention
The present invention relates to a utility vehicle and, in particular, to a utility vehicle whose cargo bed is constructed so as to be capable of a dumping operation.
2. Description of the Prior Art
For example, the specification of U.S. Pat. No. 8,833,837 discloses a utility vehicle comprising a cargo bed capable of a dumping operation.
In the utility vehicle described in the reference, the rear end part of the cargo bed is supported in a freely rotatable manner relative to the chassis. Then, the cargo bed can be raised from a normal position to a dumping position.
When the cargo bed is to be raised to the dumping position, the cargo bed is biased by manual operation or by using an assist mechanism such as a hydraulic cylinder and an air cylinder so that the front end part of the cargo bed is raised. Then, the cargo bed is held at a predetermined dumping position by using a biasing force of the assist mechanism alone.
However, in the assist mechanism in the utility vehicle of the conventional art, when the outside air temperature is extremely low (−20° C. to −30° C. or lower), operating fluid of the assist mechanism contracts so that the biasing force decreases. Thus, in some cases, the dumping position of the cargo bed varies so that the cargo bed cannot be held at a predetermined dumping position.